ADO.NET :: Select Corresponding Row In A Table Based On Selection In A Different Table

I have 3 tables (ShoppingCart, Data, Temporary) in database (Entities) I have no problems in getting data into ShoppingCart. I also know how to transfer data from columns in table ShoppingCart into columns of table Temporary (like EngName, CartID, Date, Quantity etc. - see code below) But I do not know how to multiply Quantity in table ShoppingCart by Price stored in table Data and save it into table Temporary. I think the problem is that I do not know, how to select coressponding row in table Data (see "var myCart2" in my code below) which holds the Price value for EngName previously selected by ("var myCart" also visible in the code). protected void Submit(object sender, EventArgse)

{
using (Entities
db = new Entities())
{
try
{
String
cartId = GetShoppingCartId();
var myCart = (from
cc in db.ShoppingCart
where cc.CartID ==
cartId select
cc);
foreach (ShoppingCart
item in
myCart)
{
int
i = 0;
if
(i < 1)
{
string
engname = item.EngName;
var myCart2 = (from
c in db.Data
where c.EngName ==
engname select
c);
Temporary ta =
new
Temporary();
Data d =
new
Data();